How to Use Trig Functions in Excel

Microsoft Excel is most often used for business and financial calculations, but the spreadsheet program has many scientific and technical applications as well. Many statistical, mathematical and scientific functions, including trigonometric functions, are available. Most trig functions in Excel are in the same standard form as if they were written. For example, sine is SIN, arctangent--or inverse tangent--is ATAN and hyperbolic cosine is COSH. Angles also must be converted from degrees to radians to use MS Excel's trig functions.

Instructions

1. Choose the trig function you want to use and type it into a cell, preceded by the "=" symbol and followed by the "(" symbol. If you have typed in a valid format, a small pop-up will appear that defines what parameters are still needed. If no pop-up appears, recheck your trig function. Use Excel's help function if necessary to find the correct notation. If you are using tangent, it should look like this:
   =TAN(

2. Type in the value for the angle being operated on in radians. Many times in scientific and technical operations, "radians" is the standard scale for measuring angles rather than degrees. Excel also has a function to define "pi," which makes input a little more intuitive. For example, the sine of an angle measuring 0.25 * pi radians would be entered as:
   =SIN(PI()/4)
   or
   =SIN(PI()*0.25)

3. Use Excel's conversion function if you can only find a value for an angle measured in degrees. The function RADIANS(x) converts "x" degrees to radians. The cosine of 20 degrees would be written:
   =COS(RADIANS(20))

4. Use inverse functions to find the angle associated with the given value and function. For instance, if SIN(x) = y, then ASIN(y) = x. In this case, the output, not the input, is an angle measured in radians. To find the inverse sine of 0.5 in radians, you would enter:
   =ASIN(0.5)

5. Convert the result of an inverse function to degrees, if necessary, using Excel's conversion function DEGREES. This can be used as a separate operation or directly with the inverse trig function. For example, the inverse cosine of 0.5 in degrees can be written as:
   =DEGREES(ACOS(0.5))